Fair Carrier Allocation for 5G Integrated Satellite-Terrestrial Backhaul Networks

The anticipated exponential growth in network traffic is posing significant challenges for the implementation of 5G networks. In this context, a major problem is the backhaul network which acts as a bottleneck preventing the efficient flow of ultra-dense and heavy traffic between the end users and the core network. Spectrum scarcity has emerged as the primary problem encountered when trying to accommodate the traffic upsurge. In this paper, we investigate the carrier allocation problem in the context of Integrated Satellite-Terrestrial Backhaul (ISTB) networks. In particular, we consider the satellite component to be integrated with the conventional terrestrial wireless backhaul network thus providing evident benefits in terms of data-offloading. To enhance the overall spectral efficiency of the proposed network, we consider that both terrestrial and satellite segments operate in the Ka band, where the sharing between terrestrial microwave links and satellite communications is already allowed. A novel carrier allocation algorithm based on fairness is proposed, which ensures that all backhaul links are continuously active to satisfy the operator's coverage needs. The problem is NP-hard by definition. As a consequence, we present a two-step sequential carrier allocation strategy specifically tailored to tackle the interference issues emerging from the spectral co-existence. Supporting results based on numerical simulations show that the proposed carrier allocation can provide a 2x improvement in terms of spectral efficiency when compared to benchmark terrestrial-only backhaul networks.